Sep 7, 2011
Carbon nanotubes go magnetic for targeted therapy
Researchers in Greece have made magnetic multi-walled carbon nanotubes by encapsulating iron-based nanoparticles within the host structure's graphitic tube walls (magCNTs). The hybrid material exhibits superior stability, a high-area all-carbon internal and external surface, enhanced hydrophilicity and a high drug-loading capacity, which together makes it a very promising therapeutic agent.
A big challenge in toxic drug formulations is engineering the exclusive accumulation of theraputic material at the diseased location in high concentrations, with minimal distribution to healthy tissues. Magnetic delivery is considered as one of the most promising approaches to enable such specificity and has been employed to direct a variety of metal-based nanoparticles to diseased sites by manipulation of a magnetic field.
Carbon nanotubes are emerging as superior therapy-enhancing nanostructures. This is due to their ability to move easily among tissues and penetrate into cells, and thanks to their ultra-high surface area and internal open space that can accommodate high amounts of therapeutic substances. Nonetheless, the fact that they do not exhibit magnetic properties limits their potential for targeting through magnetic delivery.
The option of filling the interior or attaching magnetic particles on the surface raises issues of i) a reduction in the significant surface area due to particle occupation, which could affect related functionalities, and ii) particle instability under magnetic field processing during in vivo application.
The team, which is based at the Demokritos National Research Center, prepared the material by combining the effect of confined growth inside the pores of an inorganic porous template with a dual-action, catalyst-carbon source to roll-up graphitic structures and encapsulate magnetic iron-based nanoparticles into tubes.
The therapeutic potential of the hybrid provided through the combination of high drug loading and directed delivery under a magnetic field is very likely to be further enhanced. A strong enhancement in MRI signal could allow early-stage diagnosis and any improvements in heat induction may open the door to additional modalities of therapy, such as radiation-induced and magnetic hyperthermia.
A collaborative investigation is under way by the Demokritos team to examine the therapeutic efficacy of the drug-loaded magCNTs in cancer cell cultures and experimental animal tumors.
Further details can be found in the journal Nanotechnology.
About the author
Dr Georgios Karanikolos is a Marie Curie reintegrated researcher at the Demokritos research center working in the field of inorganic nanostructures for biological and other applications. Dr Eleni Vermisoglou is a recent PhD graduate from the Demokritos team with expertise on carbon structures including nanotubes and graphenes. George Pilatos is a permanent staff member and an expert in growth and CVD techniques. Dr George Romanos is a permanent researcher at the Institute of Physical Chemistry working on the evaluation of sorption and permeability properties of nanoporous materials. Dr Eamon Devlin is a permanent researcher at the Institute of Materials Science responsible for the magnetic characterization of the CNT hybrids. Dr Nick Kanellopoulos is head of the Materials for Environmental Separations Laboratory (MESL) and director of the Demokritos National Research Center.